Fc functional antibody responses to adjuvanted versus unadjuvanted seasonal influenza vaccination in community-dwelling older adults

SUMMARYIn Singapore, influenza vaccination is recommended for persons at higher risk of complications of seasonal influenza, including those with chronic medical conditions and the elderly (individuals aged ⩾65 years). We investigated the factors associated with influenza vaccine uptake based on a nationally representative sample of community-dwelling adults aged >50 years. The data for this study were obtained from the National Health Surveillance Survey (NHSS) 2013. The association between influenza vaccine uptake and socio-demographic and health-related variables was analysed using univariable and multivariable logistic regression models. Of 3700 respondents aged ⩾50 years in the NHSS, 15·2% had received seasonal influenza vaccination in the past year. Older age, single marital status and economic inactivity were the socio-demographic variables independently associated with vaccine uptake. Health-related factors which were predictive of influenza vaccine uptake were sufficient total physical activity, better self-rated health, having at least one medical condition at risk of influenza complications and a regular family doctor/general practitioner. Influenza vaccine uptake in community-dwelling older adults was low. Our findings are of relevance in the formulation of public health policies and targeted health promotion strategies to increase vaccine uptake in this population group.

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Knowledge, attitudes, and practices of seasonal influenza vaccination among older adults in nursing homes and daycare centers, Honduras

PLoS ONE ◽

10.1371/journal.pone.0246382 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246382

Author(s):

Zachary J. Madewell ◽

Rafael Chacón-Fuentes ◽

Jorge Jara ◽

Homer Mejía-Santos ◽

Ida-Berenice Molina ◽

...

Keyword(s):

Older Adults ◽

Influenza Virus ◽

Nursing Homes ◽

Influenza Vaccination ◽

Seasonal Influenza ◽

Severe Illness ◽

Seasonal Influenza Vaccination ◽

Attitudes And Practices ◽

Daycare Centers ◽

Knowledge Attitudes And Practices

Background Older adults represent 70–90% of seasonal influenza-related deaths and 50–70% of influenza-related hospitalizations. Vaccination is the most efficient means of preventing influenza and reducing influenza-related illnesses. We aimed to describe knowledge, attitudes, and practices (KAP) of seasonal influenza vaccination among older adults in Honduras. Methods From August 29–October 26, 2018, we conducted a cross-sectional KAP survey regarding seasonal influenza vaccinations to samples of older adults 1) admitted to nursing homes and 2) attending daycare centers. We used the Minimental State Examination (MMSE) psychometric tool to assess the cognitive status of older adults and included participants with scores of ≥23 points in the survey. We reported frequency distributions for demographics, KAP of influenza virus and vaccination, and vaccination coverage. We used logistic regression to analyze associations between demographics and verified influenza vaccination. Results Of 511 MMSE participants, 341 completed the survey (95 adults in 12 nursing homes and 246 older adults in ten daycare centers). Almost all participants knew that influenza causes severe illness and may be transmitted from person to person, vaccination is safe and protects against disease, and older adults have greater risk of complications. Of 284 participants with verified vaccinations, 81.3% were vaccinated for influenza: 87.9% attending daycare centers and 61.4% in nursing homes. Among all participants, verified current influenza vaccination was associated with self-reported influenza vaccination in previous year (aOR: 14.05; 95% CI: 5.36–36.81); no formal education (aOR: 4.83; 95% CI: 1.63–14.37) or primary school education (aOR: 4.51; 95% CI: 1.79–11.37) having ≥secondary as reference; and indigenous (aOR: 4.55; 95% CI: 1.18–17.49) having Mestizo as reference. Reasons for vaccination were perceived self-benefits, protection against influenza complications, favorable vaccination hours, and healthcare provider recommendations. Conclusion Four-fifths of older adults were vaccinated for seasonal influenza. Educational efforts provided in conjunction with vaccination campaigns resulted in high knowledge of influenza virus, transmission, and vaccination. Further outreach regarding disease risks and vaccine safety needs to be directed towards older adults in nursing homes who had lower knowledge and coverage than older adults in daycare centers.

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Comparison of the Safety and Immunogenicity of a Novel Matrix-M-adjuvanted Nanoparticle Influenza Vaccine with a Quadrivalent Seasonal Influenza Vaccine in Older Adults: A Randomized Controlled Trial

10.1101/2020.08.07.20170514 ◽

2020 ◽

Author(s):

Vivek Shinde ◽

Iksung Cho ◽

Joyce S Plested ◽

Sapeckshita Agrawal ◽

Jamie Fiske ◽

...

Keyword(s):

Older Adults ◽

Influenza Vaccine ◽

Seasonal Influenza ◽

Controlled Trial ◽

Geometric Mean ◽

Community Dwelling ◽

Antibody Responses ◽

Influenza Vaccines ◽

P Values ◽

Cytokine Analysis

Background: Improved seasonal influenza vaccines for older adults are urgently needed, which can induce broadly cross-reactive antibodies and enhanced T-cell responses, particularly against A(H3N2) viruses, while avoiding egg-adaptive antigenic changes. Methods: We randomized 2654 clinically-stable, community-dwelling adults ≥65 years of age 1:1 to receive a single intramuscular dose of either Matrix-M-adjuvanted quadrivalent nanoparticle influenza vaccine (qNIV) or a licensed inactivated influenza vaccine (IIV4) in this randomized, observer-blinded, active-comparator controlled trial conducted during the 2019-2020 influenza season. The primary objectives were to demonstrate the non-inferior immunogenicity of qNIV relative to IIV4 against 4 vaccine-homologous strains, based on Day 28 hemagglutination-inhibiting (HAI) antibody responses, described as geometric mean titers and seroconversion rate difference between treatment groups, and to describe the safety of qNIV. Cell-mediated immune (CMI) responses were measured by intracellular cytokine analysis. Findings: qNIV demonstrated immunologic non-inferiority to IIV4 against 4 vaccine-homologous strains as assessed by egg-based HAI antibody responses. Corresponding wild-type HAI antibody responses by qNIV were significantly higher than IIV4 against all 4 vaccine-homologous strains (22-66% increased) and against 6 heterologous A(H3N2) strains (34-46% increased), representing multiple genetically and/or antigenically distinct clades/subclades (all p-values <0.001). qNIV induced 3·1- to 3·9- and 4·0- to 4·9-fold increases in various polyfunctional phenotypes of antigen-specific effector CD4+ T-cells against A(H3N2) and B/Victoria strains at Day 7 post-vaccination, respectively, while corresponding fold-rises induced by IIV4 at Day 7 were 1·3-1·4 and 1·7-2·0 representing a 126-189% improvement in CMI responses for qNIV (all p-values <0·001). Local reactogenicity, primarily mild to moderate and transient pain, was higher in the qNIV group. Interpretation: qNIV was well tolerated and produced a qualitatively and quantitatively enhanced humoral and cellular immune response in older adults. These enhancements may be critical to improving the effectiveness of currently licensed influenza vaccines.

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